The field of the invention is shock absorbers and the invention relates more specifically to shock absorbers for motorcycles and other small vehicles which are typically provided with springs mounted to the shocks.
Unlike automobiles, most motorcycles are suspended by springs which are an integral part of two pairs of shock absorbers. Various means have been used to adjust the level to which a shock absorber spring will suspend a motorcycle. Some motorcycle shock absorbers are equipped with a three or five step spring seat whereby the spring preload may be set by use of a wrench. In order to facilitate adjustment, another and different approach at shock absorber leveling has resulted from the use of a gas filled bladder positioned between the relatively moveable parts of the shock absorber. By partially inflating the bladder the amount of pressure between the relatively moveable parts of the shock absorber is increased and the shock absorber will hold the motorcycle in a slightly higher position, or restore any position lost as a result of loading.
The adjustment of the spring seat by use of a wrench is useful in initially setting up the motorcycle but cannot be used while the motorcycle is in use. Furthermore, if the motorcycle is equipped with saddlebags, spring seat adjustment is very time consuming. The use of a gas bladder requires stopping at a source of pressurized air for adjustment. Of course if the bladder is punctured or otherwise has a gas leak, the leveling capacity is lost.
A system is needed to permit load leveling adjustment, which adjustment can be made during the riding of the motorcycle. Since road conditions vary from a level freeway to a road with a steep grade, the requirements of the shock absorber can vary during the same trip even with the same load. Of course, when motorcycle loads are changed this need for shock absorber adjustment is more critical as, for instance with the addition of a passenger.